[gnome-panel] doc: add panel-plug-private.h to ignore list

[Alberts Muktupāvels <muktupavels src gnome org>]

commit d7d0f58e19df800aaf98dddd8542f426adc83e78
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Apr 16 22:08:20 2016 +0300

    doc: add panel-plug-private.h to ignore list

 doc/reference/libpanel-applet/Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/doc/reference/libpanel-applet/Makefile.am b/doc/reference/libpanel-applet/Makefile.am
index ced67bb..1ee58f8 100644
--- a/doc/reference/libpanel-applet/Makefile.am
+++ b/doc/reference/libpanel-applet/Makefile.am
@@ -51,6 +51,7 @@ IGNORE_HFILES = \
        panel-applet-factory.h \
        panel-applet-marshal.h \
        panel-applet-private.h \
+       panel-plug-private.h \
        $(NULL)
 
 # Images to copy into HTML directory.